Hugh Herr is a professor at MIT and co-director of MIT Center for Extreme Bionics. Dr. Herr is creating bionic limbs that emulate the function of natural limbs. His research and work has led to an emerging field of biomechatronics in which bionic prostheses integrate seamlessly with human physiology.
“In today’s society, we make clear distinctions between the biological body and the designed world. Such distinctions will become less and less clear as we progress through this 21st Century.”
Please tell your background and how did you get here. (Hugh Herr) A very long story, I was an elite mountain climber specifically in the realm of rock climbing when I was in my teens. And then during my 17th year, I was in a mountain climbing accident and suffered from frostbite to my lower legs. After several months of effort, my medical team abandoned their effort to save my biological lower limbs, and they proceeded to amputate both of my legs just below the knees. Since then, I’ve been wearing artificial limbs to walk and to run and to climb. The first limbs that were provided me after my legs amputated were very crude. Lacking technological sophistication, the prostheses did not have sensing, synthetic computation, or muscle-tendon actuation. Basically, the synthetic limbs that were provided me were passive and inert and incapable of emulating biological function. So when I was first given these crude prostheses, I was shocked and I said to myself, there has to be a better way. And during that time I dedicated my life to redesigning synthetic body parts. As a young man I imagined a future in which for conditions even as severe as amputation, science and technology could enable a return to full physicality and even beyond full physicality into realms of augmentation.
“My MIT research group develops technology for human augmentation — technology to augment a person with a normal physiology, such as exoskeletons that enable people to jump higher, run faster and move with less musculoskeletal stress.”
What is Biomechatronics and where can we see the application of this field? (HH) Biomechatronics describes an area of science and technology that merges the biological body with synthetic mechatronics. In fact, my research group at MIT is called the Biomechatronics Group located in the MIT Media Lab.There we develop extreme interfaces between human physiology and synthetics. We look at how machines can be attached to the body electrically or neurally, how they can be attached mechanically as well as dynamically. So it’s through our research that we’re developing really cutting edge bionic appendages that are enabling people with, for example, limb amputation and other types of limb pathology to return as close as possible to full physicality. My research group also develops technology forhuman augmentation — technology to augment a person with a normal physiology, such as exoskeletons that enable people to jump higher, run faster and move with less musculoskeletal stress.. So both in rehabilitation and augmentation. We’re applying the fundamentals of bionics.
You’ve previously mentioned that ‘what is biological and what is not, what is human and what is not, what is nature and what is not will be blur’ can you elaborate what do you mean by this? (HH) In today’s society, we make clear distinctions between the biological body and the designed world. Such distinctions will become less and less clear as we progress through this 21st Century. When we intimately connect the human nervous system to a mechatronics limb, for example, where the nervous system is embedded, if you will, into the mechatronic device bi-directionally, the human that’s using the mechatronic limb no longer views the mechatronic limb as separate from their body, or as a separate tool. But in fact, they view it as part of their body, integral to their body, redefining their self image. So in the future, we’ll see more and more of that level of integration between our biological bodies and the designed world where we can actually architect our own bodies through design, and fundamentally change how we see ourselves morphologically, dynamically, and cognitively.
“Each of my bionic legs has within them three small computers and 12 sensors. These small computers receive the sensory information of position, speed, acceleration, force and temperature.”
Please tell about your bionics you’re wearing right now. And how do they work? (HH) So I am wearing two bionic ankle-foot prostheses that were developed in my research group and are now made available commercially by a company called Ottobock in Europe. Each of my bionic legs has within them three small computers and 12 sensors. These small computers receive the sensory information of position, speed, acceleration, force and temperature. And then there is an algorithm that is informed by such sensory data to control how a muscle-tendon like motor system creates torque and stiffness as I move. Through this technology, I’m able to stand, walk and run in a very natural and biological way, even though my lower legs are completely synthetic.
How much average bionics would cost now and how could we make this technology be affordable to general public? (HH)The limbs that I am currently wearing are very high-tech, and they’ve only recently been developed so they’re quite expensive. But like all new technologies, as they mature and as they are scaled, the price point will lower in time. Our smartphones are technologically sophisticated, but are offered today at a modest price point. Such will be the case with bionic appendages; in time with commercial scale, the price will come down to manageable levels.
“At MIT we invented a new way of amputating limbs called the Agonist-antagonist Myoneural Interface, or AMI for short.The AMI procedure restructures the tissues in a way that improves neural communication between the prosthesis and the human peripheral nervous system.”
Your team at MIT developed the Agonist-antagonist Myoneural Interface, or AMI for short, that allows humans to sense their prosthetic limbs. How is the AMI different to technology that existed previously? (HH) So remarkably, the way limbs are amputated using the standard-clinical-of-care amputation procedure hasn’t changed since the U.S. civil war.The field has seen all this progress in technology for the external robotic limb, for example synthetic sensors and small microprocessors. But how limbs are amputated and how the tissues are manipulated fundamentally hasn’t changed in the standard-of-care practice. So at MIT we invented a new way of amputating limbs called the Agonist-antagonist Myoneural Interface, or AMI for short. The AMI procedure restructures the tissues in a way that improves neural communication between the prosthesis and the human peripheral nervous system. What we do specifically is we link muscles to create natural dynamic pairs. So, for example, an intact biological leg, when the ankle flexes and extends, the calf muscle is dynamically related to the muscle in the front of the leg called the tibialis anterior; when one muscle shortens, the other muscle lengthens (and vice versa). That dynamic muscle interplay provides sensory information to the central nervous system, communicating muscle length, speed and load. This phenomenon is called proprioception. So with the AMI amputation, we create dynamic muscle pairs so that the brain receives proprioceptive information of prosthetic joint movements. When a person with limb amputation moves their phantom limb, and when they look down and see their bionic limb, they experience natural sensations of movement as they move or reposition the bionic limb at different postures and speeds.
Jim Ewing climbing in the Caymans – Rebuilt as a cyborg, Jim returned to the Cayman Islands, the site of his accident, to climb once again. Video courtesy of STAT.
You are a rock climber yourself. Could we expect in the future where the bionics would have enough technology and data to be able redirect us what is best way go climb in each trail? (HH) The first human that received the AMI amputation is a friend of mine; his name is Jim Ewing. Jim was in a traumatic accident. He was rock climbing, and he fell 50 feet when his rope failed to catch him. He hit a very rocky ground surface and did tremendous damage to his physical body. One of his legs was particularly damaged. So much so that Jim received the AMI amputation procedure at Brigham & Women’s Hospital in Boston by surgeon Matthew Carty. After the surgery, we then built Jim a cyborg rock climbing leg. He returned to the Cayman islands, the site of his accident, and he triumphantly climbed once again with the cyborg limb. Under brain control, he moved up the rock face with his cyborg limb moving under his command, feeling natural sensations of how the cyborg limb was moving as he traversed up the vertical cliff. So that’s where we are today. As we march into the future, these cyborg limbs will become better and better, augmenting all kinds of sporting activities inclusive of rock climbing.
“Bionics will certainly traverse into a prevalent technology that’s used by everyone, whether as a rehabilitation technology, or as an augmentative technology such as powerful exoskeletons that enhance jumping height and running speeds.”
Why is the human augmentation will be our future selves? (HH) Bionic and Cyborg technologies are used today largely in the realm of rehabilitation after a person suffers from a traumatic injury or disease. Bionics will certainly traverse into a prevalent technology that’s used by everyone, whether as a rehabilitation technology, or as an augmentative technology such as powerful exoskeletons that enhance jumping height and running speeds. For example, an exoskeleton is an augmentation device that attaches to the human arms, legs, your torso, in order to fundamentally make us stronger, more powerful or faster. Within my research group at MIT and my new company, Dephywe’re building such exoskeletons to make humans faster and stronger and more agile. At my company Dephy we’re redesigning what shoes are, and making them bionic. Using the Dephy technology, any person can put the bionic shoe on and jump higher, run faster or more efficiently. Because of our work, as well as the development work of other researchers, I believe such technologies will impact everyone globally in the coming decades.
“There’ll be some point in this Century when the Paralympic athlete’s performance will exceed that of the Olympic athlete’s performance. That is to say, Paralympic athletes will jump higher and run faster compared to Olympic athletes.”
How do you see the future of Olympics, specially Paralympics? (HH) Because of advancements in technology, the Paralympics have become more and more interesting. You know, fundamentally, many Paralympic events can be described as human-machine sporting activities, whereas the Olympics typically are a celebration of what the biological human body can do at the extremes of training and performance. As bionics becomes more and more advanced, as human augmentation becomes more and more advanced, the running times, the jumping heights, the swimming performances within the Paralympics will all become better and better and better. And there’ll be some point in this Century when the Paralympic athlete’s performance will exceed that of the Olympic athlete’s performance. That is to say, Paralympic athletes will jump higher and run faster compared to Olympic athletes. And when that happens, I believe spectators will prefer the Paralympics over the Olympics.This time will indeed be very interesting in sport. And as we progress towards the latter half of the century, I do believe the Olympics will be viewed by spectators as dull and boring, but the Paralympics will be viewed as remarkably exciting.